Titanium base alloys



United States Patent TIT BASE ALLOYS Robert I. .l'aifee, Worthington, and Horace R. Ogden and Daniel J. Maykuth, Columbus, Ohio, assignors, by mesne assignments, to Rem-Cm Titanium, Ind, Mi..- land, Pa., a corporation of Pennsylvania NoDrawing. Application December '7, 1953, Serial No. 396,756

12 Claims. (Cl. 75-1755) This invention pertains to improvements in titanium base alloys, and provides a series of alloys of high, strength and ductility, and, as to certain analyses, also of high contamination resistance and high strength at elevated temperatures, and containing as essential constituents titanium and tin, together with one or more additional metals selected from the groups comprising alpha promoters, beta promoters and compound formers as enumerated below.

This application is a continuation-impart of our copending applications S. N. 285,076, filed April 29, 1952, now Patent No. 2,669,513, issued February 16, 1954, and S. N. 294,262 and 294,263, both filed June "18, 1952, and S. N. 344,686, filed March 25, 1953, each now abandoned.

The tin content may be present over a broad rangeof about 0.5 to 23%, with a preferred lower'limit of about 2.5%, as adjudged from the standpoint of good room temperature mechanicalproperties, and apreferred lower limit of about as regards the imparting of high contamination resistance at elevated temperatures. To the titanium-tin alloy aforesaid, there may advantageously be added up to about 17% in aggregate of one or more of the alpha promoters, up to about 50% in aggregate of one or more of certain of the beta promoters, and up to about 2 or 3% in aggregate of the compound formers, all as set forth more in detail hereinafter. For further enhancing the mechanical properties, the alloys .of the invention may contain controlled amounts of the interstitials, carbon, oxygen and nitrogen. For certain analyses, as set forth below, carbon may be present up to about 1%, oxygen up to about 0.5% and nitrogen up to about 0.4%. For a tin content below about 5%, and particularly below about 2.5%, substantial addition of one or more of the interstitials carbon, oxygen and nitrogen or of metal of the'alpha and/ or beta promoter groups, is required for imparting adequate tensile properties for commercial applications, as'elaborated upon below.

As above stated, the alloys of the inventionare in general characterized by excellent room temperature mechanical properties, possessing high tensile strength as compared to the unalloyed titanium base metal, combined with adequate ductility for both hot and cold forming operations, i. e., forging, rolling, drawing, extruding, etc. For tin contents up to about 16%, they may likewise, in general, be welded without appreciable loss of ductility in the welded as compared to the non-welded portions. This is particularly true as regards'those alloy having an all-alpha microstructure, and also as to certain of those having a beta-containing microstructure, as explained more in detail below.

.For imparting a high degree of contamination resistance, i. e., resistance against penetration by atmospheric gases, particularly oxygen and nitrogen, at elevated temperatures up to about 1100 C., the alloys should contain upwards of about'5% tin, although lesser amounts .down to about 2% tin are materially beneficial in this respect. Tin alloyed with titanium base metal appears to be unique in imparting thi contamination resistance, and its cited 2,797,995 Patented July 2, 1957 ICC is quite critical with respect to the degree of contamination resistance imparted commencing at a minimum of about 5% tin.

These contamination resistant alloys are also characterized by free scaling properties resulting from exposure to elevated temperatures up to about 1100 C. and to atmospheric, oxidizing, or alternately oxidizing and reducing conditions. That is to say, the scale formed is easily brushed oil or flakes off during hot forming operations, such as forging or rolling.

As is known, the metal titanium in the pure state, is capable of existing in either of two allotropic forms. Below a temperature of about 885 C. or 1625" F., it assumes a close-packed hexagonal structure known as the alpha phase, while at this temperature and above it assumes a body-centered cubic structure known as the beta phase.

Certain substitutional alloying additions to the titanium base metal, among which may be mentioned aluminum, tin, antimony, indium, silver, bismuth, lead, cadmium, zinc, and thallium as Well as the interstitials carbon, oxygen, and nitrogen may be termed alpha stabilizers or alpha promoters. The term alpha stabilizer includes those elements which raise the transformation range sharply, such as aluminum, oxygen, and nitrogen. Also alpha stabilizers include elements such as carbon, which have a relatively small solubility in alpha titanium, but which raise the transformation temperature for that amount which is in solution. Alpha stabilizers also include those elements such as tin, antimony, indium, and silver which have relatively large solubilities, of about thesame magnitude, in both the alpha and beta phases and which have little effect on the transformation temperature range, neither raising nor lowering it markedly. A common characteristic of all alpha stabilizers, as we are considering'them here, is that little or no hardening occurs in the thermal processing. The resulting alloys are, at room temperature, always all alpha in structure regardless of the heat treatment, including quenching or aging. Actually little is known concerning the specific effects of bismuth, lead, cadmium, zinc, and thallium on the transformation range. These alloying elements produce alloys which fitthe criteria given, namely, that they form all-alpha alloys, which do not retain any substantial content of betaphase nor harden appreciably on quenching from the beta field. Hence these elements appear properly classified as alpha promoters, and will be so treated in this application.

Other substitutional alloying elements, when added in progressively increasing quantities, stabilize the beta phase at progressively lower temperatures, until a mixed alpha-beta or stable all-beta microstructure is obtained at normal or atmospheric temperatures, or the beta phase undergoes a eutectoid reaction, depending on the character and amount of the beta stabilizers added as discussed below.

Speaking in broadest terms, the beta stabilizer are Mo, V, Cb, Ta, Zr, Mn, Cr, Fe, W, Ni, Co and Cu. Silicon and beryllium-may also be considered as beta stabilizing elements, but their solubilities in titaniumare relativelyso slight and the tendency of the beta phase stabilized by these elements to decompose into eutectoid productsso great, that it is equally proper to consider them as compound-forming elements. Within this broad category, however, only certainof the elements mentioned are suitable for producing mixed-phase, alpha-beta alloys, or all-beta alloys. These are the element which have beta-isomorphous diagrams, or which have beta-eutectoid diagrams such-that the decomposition of the beta phase into eutectoid is so sluggish that the alloys behave like those in a beta-isomorphous system. The beta stabilizing-elements of this type are Mo, V, Cb, Ta, Mn, Fe and Cr. sluggishly decomposing and rapidly decomposing types and hence may be classified either Way. Within this limited group only Mo, V, Cb and Ta are beta-isomorphous. They form the most thermally stable beta-containing alloys, as a result of their beta-ismorphism.

Zirconium is a beta promoter or stabilizer in the sense that the lowest temperature at which alloys thereof with titanium are entirely beta, becomes progressively lower with increasing amounts of zirconium, until a composition is reached at which this so-called beta transus temperature starts to increase again with further additions of zirconium. While zirconium thus lowers the transformation temperature of titanium, the alloys eventually revert to the alpha phase at lower temperatures unless other beta-promoters are present. Zirconium is isomorphous with titanium both in the alpha and beta fields. As a result, it is proper to consider zirconium together with vanadium, molybdenum, columbium and tantalum as all being beta-isomorphous with titanium.

The use of copper alone as an alloying addition to titanium, does not fit into the above-mentioned grouping of beta-isomorphous and sluggishly decomposing eutectoid beta promoters, because the beta phase stabilized by copper always decomposes rather rapidly into pro-eutectoid and eutectoid products, and the same is generally true with respect to cobalt, nickel, silicon and beryllium, above listed under the broad category of beta stabilizers. Copper, however, is a useful addition when present as a minor alloying element, for example, up to a few percent, in alloys containing larger amounts of other beta-stabilizing elements, within the narrow group of elements last mentioned above since, in these low concentrations and in the presence of such other beta-stabilizing elements, the tendency of the beta phase stabilized in part by copper to decompose into eutectoid products is minimized or entirely eliminated.

The tolerance of the ductile TifiSn base alloys of the invention with respect to additions of the various betapromoters above mentioned, varies considerably for the individual elements of this group, being greatest with respect to those which form beta-isomorphous systems with titanium, and least for those which decompose most readily into eutectoid decomposition products. Thus, the TiSn base alloys may be strengthened without undue embrittlement by additions of up to about 50% in aggregate of elements composing the beta-isomorphous group, viz., molybdenum, vanadium, columbium, tantalum and zirconium, since these elements are soluble in all proportions in beta titanium. Of the sluggishly decomposing elements, the base alloy will tolerate additions of up to about 20% of either or both chromium and tungsten, up to about 10% manganese, and up to about 7% iron. Metal of the group cobalt, nickel and copper may be added up to a total of about For additions of all of the above-mentioned beta-promoters, the lower effective limit is about 0.5% and preferably about 1%.

The tolerance of the ductile TiSn base alloys for the alpha promoters depends on the amount of tin present, the less tin present the greater the amount of alpha promoters that can be added, and vice versa. Aluminum may be added to a maximum content of 8%, and antimony may be added to a maximum content of 17%. The proportioning of aluminum and antimony contents in relation to the tin content are given below. Indium may be added up to a maximum content of 15%. Silver may be added up to about 20%. Cadmium, zinc, thallium, bismuth and lead may be added up to 15% each, added to the charge in melting. The lower efiective limit for the alpha promoters is about 0.5% and preferably about 1%.

The elements Ce, B, As, S, Te and P are strictly compound-forming elements. They do not have appreciable solubilities in either the alpha or beta phases, but form intermetallic compounds with titanium. The beta pro Tungsten is a borderline element as between the moters silicon and beryllium are likewise best grouped as compound-forming elements, in view of their abovementioned low solubilities in titanium and the tendency of the beta phase stabilized by these elements to decompose rapidly into eutectoid products. The Ti-Sn alloys of the invention will tolerate only relatively small amounts of these compound-forming elements, i. e., up to a total of about 2 or 3% maximum, the lower effective limit being about 0.1 or 0.2%.

Substantially pure and ductile metallic titanium may be produced at considerable expense by the so-called iodide process described in U. S. Patent 1,671,213 to Van Arkel; while ductile titanium of commercial purity is produced more cheaply by the magnesium reduction of titanium tetrachloride by the process described in U. S. Patent 2,205,854 to Kroll. Both procedures, particularly the latter, result in some contamination of the titanium metal With-one or more of the interstitials, carbon, oxygen and nitrogen. But since, as noted above, these are all alpha-promoting or stabilizing elements, the resultant somewhat contaminated titanium metal obtained, has at room temperatures a single phase, all-alpha microstructure.

The all-alpha, all-beta and mixed alpha-beta alloys of titanium have their respective advantages and disadvantages. Generally speaking, the alpha alloys provide good all-around performance, having good weldability, and being strong and resistant to oxidation, both cold and hot, but are somewhat inferior as to ductility. The all-beta alloys, on the other hand, have excellent bendability and ductility, are strong both hot and cold, but are somewhat vulnerable to atmospheric contamination, particularly at elevated temperatures. The mixed alpha-beta alloys provide a compromise performance as between all-alpha and all-beta alloys, being strong when cold and warm, but weak hot, while possessing good bendability and ductility, with a moderate degree of resistance to atmospheric contamination.

Since the Ti-Sn base alloys have, as above noted, an all-alpha microstructure, they may be readily welded in tin contents up to about 16%, with no appreciable impairment of ductility in the welded as compared to the non-welded portions. They also form an excellent base alloy for the ternary and higher component alloys of the invention, that may be also welded without appreciable loss of ductility in the welded as compared to the nonwelded portions. This is particularly true as regards the above-mentioned alpha-promoter additions to the base alloy. Also, in general, the ternary and higher component alloys made by additions of the beta-isomorphous elements above designated, are weldable without appreciable impairment of ductility. It may furthermore be stated that in general the alpha-beta alloys according to the invention can be produced to have ductile welded portions if suitable post-welding heat treatments are applied as de scribed in the co-pending application of Robert I. Jafiee, Horace R. Ogden and Ralph A. Happe, Serial No. 305,504, filed August 20, 1952, now abandoned.

Antimony is a particularly valuable addition to the titanium-tin base metal as it imparts about the same strengthening efiEect as equivalent additions of tin. As the tin content increases, the tolerance for antimony decreases and vice versa with respect to retention of adequate ductility, in accordance with the following tabulation:

TABLE A Percent tin: Percent antimony max. 1 17 5 I 15 10 10 17.5 5 23 0.5 A somewhat similar relationship applies as between the tin cont nt and the permissible range of aluminum additions consistent with retention of adequate: ductility, as

Tin is soluble in alpha titanium to the extent of at follows: least 15%, and alloys of titanium with up to 15% tin TABLE B are all in the alpha phase. As the tin content is increased, the beta transformation temperature rises, and at a temg Percent alummnm perature of about 930 C., and a tin content of about 6 19%, a peritectoid reaction occurs. In alloys containing 5 5 about 20 to 23% tin, two intermediate phases formed at 4 5 different temperatures have been tentatively identified. The following Table I gives, for comparative purposes 3 10 with the further test data presented hereinafter, test results 23 1 showing the improvement in mechanical properties, resulting from additions of. tin over the range of about 1 to Antimony has the same strengthening efiect on the above 23%, to both iodide and commercial purity titanium titanium-aluminum-tin alloys as equivalent additions of base metal, with and without further controlled additions tin and may be substituted therefor in the proportions 15 of one or more of the interstitials, carbon, oxygen and above set forth in Table A. nitrogen:

TABLE I Ti'-Sn binary alloys [Annealed condltionJ Composition, Percent Tensile Properties: (Balance Titanium) p. 8.1. X 1,000

Percent Percent Vickers Min. Elongation Reduction Hardness Bend'l 0.2% Ultimate in 1" in Area Sn 0 0 N Ofiset Strength Yield IODIDE TITANIUM BASE PURITY TITANIUM BASE 48 73 21 54 198 0.8 2.5 67 86 14 48 236 1.5 5 71 99 14 42 246 1. 5 10 91 11 36 296' 1.5 15 108 123 10 35 313 2.3 20 123 131 10 39 330 2. 2 22. 5 139 150 5 19 341 2. 2 5 96 106 27 61 311 1.8 4 113 121 26 60 335 1.8 5 121 129- 7 11 367 3.0 5 109 123 24 53 351 2.5 5 137 148 8 10 403 Brittle 5 0. 28 142 149 12 31 388 7. 4 5 0. 42 159 164 1 8 415 Brittle 10 112 118 26 53 356 1. 9 10 148 148 11 32 385 4. 5 13 109 19 45 1.8 10 122 131 19 44 358 2. 8 10 131 138 16 39 386 3.3 10

Fromv these results it will be observed that additions of tin up to about 23% greatly strengthen the metal while retaining adequate ductility for fabrication purposes, i. e.',' forging, rolling, etc. For the iodide titanium base the yield strength is more than quadrupled from 27,000 to 135,000 p. s. i., while the ultimate strength is more than tripled from 43,000 to 149,000 p. s. i. For any given tin content further strengthening results from controlled additions of one or more of the interstitials. Thus, at the tin level, the addition of 0.5% carbon, approximately doubles the yield and ultimate strength without reducing ductility. Oxygen and nitrogen additions have generally similar effects as shown. In this way the tensile strength of the material may be raised to as much as about 160,000 p. s. i. with retention of adequate ductility as shown, for example, by the 19% tin, 0.2% carbon, commercial purity base analysis.

Considering now the strengthening efiects of additions to the titanium-tin base alloys as typified" by Table I, of one or more of the alpha promoters, beta promoters, or compound formers above discussed, the following Table II gives test results for additions of oneof the more important beta promoters, namely, manganese:

TABLE n increases ranging up to'about 160,000 p. s. i. with addi-' as compared to the alloy omitting manganese, while at the same time increasing the ultimate strength uplto about 150,000 p. s. i. The eifect of interstitial additions to the manganese-containing alloy again enhances'the strength without serious eiiect on ductility as shown by comparison of the 9% tin,'2.5 and 5% Mn analyses.

The following Table III shows the efiects of molybdenum additions to the titanium-tin base alloy. Here again, as in the case of manganese, the molybdenum additions greatly increase the strength of the alloy while retaining adequate ductility. For example, with the 10% tin analysis and a 7.5% molybdenum addition, the ultimate strength is increased from 110,000 to 140,000 p. s. i. with no loss in ductility, as shown by comparison with Table I. At the 15% tin level the ultimate strength is increased from 123,000 to 167,000 p. s. i. with no loss in ductility upon the addition of 5% molybdenum. The efiect of adding interstitials is shown by comparison of the values for the 9% tin, 2.5% molybdenum analysis Ti-Sn-Mn alloys (commercial titanium base) [Annealed eonditioml Composition, Percent Tensile properties:

(Balance Titanium) 1). s. i. 1,000 Percent; Percent Elongation Reduction Vickers Min. Bend in in Area Hardness T Sn Mn 0 O N 0.2% Ultimate Ofi'set ield Strength 9 74 89 21 276 1. 7 9 0. 25 72 90 20 48 261 1. 6 9 0.5 74 24 49 273 1. 7 9 0. 5 113 122 20 55 369 1. 5 9 0. 5 96 117 20 45 364 1. 6 9 0.5 94 20 46 344 1. 5 9 2. 5 107 118 11 46 336 1. 2 9 2. 5 138 143 19 39 369 1. 8 9 2. 5 144 17 39 389 1. 8 9 2. 5 143 13 46 397 2. 8 9 5 130 140 16 90 353 1. 7 9 5 0.2 153 157 16 37 424 4. 7 9 5 0.2 151 156 14 36 421 4.8 9 5 0. 2 146 153 12 38 426 2. 3 9 7. 5 120 129 10 11 350 1.6 10 1 110 118 12 44 341 1. 6 10 2 121 128 15 48 326 1. 7 10 3 132 141 15 51 356 1. 4 10 4 129 140 15 39 363 1. 6 10 5 135 144 12 25 375 1. 4 10 6 144 151 16 38 369 1. 4 10 7 143 147 9 35 385 1. 2 10 8 151 154 9 27 386 2. 9 10 9 154 157 10 29 377 3. 7 10 12 171 173 2 Br 404 Br 1 5 97 111 20 49 316 0.8 5 5 116 126 14 41 324 1.6 15 5 160 4 15 431 7.0

Comparing the results of the above table withthose given in Table I, it will be seen, for example, that for the 10% tin alloy containing no manganese, the ultimate strength is 110,000 p. s. i., as compared to progressive wherein the ultimate strength is increased from 113,000 to the order of 130,000 to 140,000 p. s. i. with no appreciable effect on ductility. The same order of increase occurs at the 9% tin, 5 molybdenum level.

TABLE IV [Annealed Condition] Id .mm 64 1 60 m67979961875 9971755465753 MB LLl UL LLLLQQLOMLQLBLLLLLZQMZLZLOMZ S Hague. 5 9 9 8 03 58616199 663 2 MM 6H2 7um9mm%m35%33%3%%4swnmm5w nww WHn 223 2332333 33333 4 3333 33 33 mmnm E mmmA m%% S wwfimmmmmwmwfiwfifl mflwwwmmfifimmuhfi P .m E m S t fi" m m mwn l 207 9937056564620158718748783391 PE U A I T N I 1 6 T .M Meow M 78 L 238 41 0060 3836191535127 HM .mm I 99% A 123W00%2343%4455332234234M%% 0L. I tn T 1 I 111 11111111111111.1111111111 mm ms m m Pi I E e s n. %m W 857 M 2420187293 101 15344. 53268 W 251m I 781 M 0137881524fi344M52311M30133WW O of the same general order of magnitude as for the molybdenum addition and hence requires no detailed comment.

[Annealed condition} The observed improvement is Ti- -Sn--Mo' alloys 0 .mmT 006 0266777881283635634 7855505 MB 12 1 LLLLLLLQQLQLZLnALLOmLLLnmnAQmLnw S m 314 8 80934 2849228694235564 1 .2 N 260 6%009180912657666947665M08 HR 223 22332323233333333333333332 t mwnm 14.2 E 4.3205 788 6095172658603173 mwmA E 4 42 "5 65554%133fi2354555443333312 P m S B t M M t V mwvn U 8 1 1 mmm U UB mmflmmuwwl fiflmmnmmulumm 1 PE M m t t A I E wh T T k I L mm m T mun w 0 S X. R e 5 0 m oflfi I I M m 2m QMW M M T Y 1 o 1 U Composition, Percent (Balance Titanium) l a u m a O o x t 555 M 555 55 5 5 222556655 1 o n 55 11 111 Table IV below shows the effect of chromium additions to the titanium-tin base.

Table V shows the eflect of adding iron to the titanium tin base. It will be noted by comparison with Table I that the iron addition tremendously increases the ultimate strength accompanied in general by retention of adequate ductility. With the 15% 'tin analysis and a titanium base of commercial purity, the addition of 2% iron increases the ultimate strength from 123,000 to 177,000 p. s. i.

with substantially no change in ductility. At the 10% tin level, the ultimate strength is increased from 110,000 to 150,000 p. s. i. with no change in ductility upon the addition of 4% iron. Here again, as in the previous data, the addition of the interstitials enhances the strength properties with no loss in ductility as can be seen by comparison of the 9% tin, 0.5% iron analyses:

TABLE V Ti-sn-Fe alloys [Annealed condition] Composition, Percent Tensile Properties:

(Balance Titanium) p. s. i.X1,000 Percent Percent Reduc- Vickers Min. Elongation in Hardness Bend '1 0.2% Ultimate tion in 1 Area Sn Fe Other Ofiset Strength Yield IODIDE TITANIUM BASE COMMERCIAL TITANIUM BASE 1 2 77 104 16 42 255 1. 3 4 5 97 124 17 27 2. a 2 120 125 18 38 328 3.6 9 0. 25 74 20 42 278 2. 5 9 0. 5 74 99 18 39 294 2. 7 9 1. 25 96 112 19 46 320 1.6 9 2. 5 120 132 15 39 349 1. 3 9 5 103 0 0 375 Br 9 a 7. 5 115 0 0 382 B1 a 1. 5 108 120 18 40 330 1. 8 10 2 121 132 9 31 347 1. 5 10 3 133 147 14 36 359 2. 0 10 4 137 150 10 37 370 1. 5 10 5 185 190 5 16 446 Br 10 7. 5 176 179 8 31 426 6.1 2 170 177 12 32 411 2. 3 9 0.25 0.250 113 119 25 54 343 2. 5 9 0. 25 0. 106 122 21 38 341 2. 3 9 0. 0. IN 91 109 21 36 304 2. 3 9 0. 5 0. 250 104 125 24 50 338 1. 3 9 0.5 0. 20 105 125 16 40 321 1. 8 9 0. 5 0. 1N 105 17 42 306 2. 4 9 1. 25 0. 20 123 134 17 27 362 1. 7 9 1. 25 0.20 110 123 17 42 383 1.9 i 9 l. 25 0. 2N 126 142 16 45 380 1. 7 9 2. 5 0.20 a 143 152 18 396 1. 5 9 2.5 0.20 139 152 15 41 408 2.3 9 2. 5 0. 2N 153 164 15 34 404 Br TableVI below shows the effects of additions of the beta stabilizers vanadium, tungsten, columbium, tantalum, copper, zirconium, cobalt, and nickel to the titanium-tin 50 base.

. TABLE VI Ti-Sn base plus V, W, Cb, Ta, Cu, Zr, Co, Ni, Si, Be

alloys [Annealed conditionJ Composition', .Percent Tensile Properties:

(Balance Titanium) p. s. i.X1,000 Percent Percent Elon- Reduc- Vickers Min.

I 0 gation tion in Hardness Bend T Sn 7 Other g Ultimate in 1" Area Yield Strength IODIDE TITANIUM BASE 10 2.5V 78 97 10 16 276 0.5 10 2.5W 84 106 7 36 258 0.6 10 2.50b 54 76 16 47 263 1. 1 1O 2.51a 68 81 12 53 259 1.7 5 1011 72 19 32 269 3.1 1011 75 94 15 29 276 2.0 15 1011 112 29 322 2. 9 10 1011-020 98 108 22 38 340 1. 9 10 1011-020 94 108 14 37 347 3. 4 10u-0.2N 114 128 11 28 375 6. 3 10 2.5Zr 92 110 40 270 2. 2 1 2.5Zr0.20 117 18 43 356 2. 1 10 2.5Zr-0.2O 99 113 18 42 318 3. 7 10 2.5Zr-0.2N 129 136 15 39 369 3. 3 10 2.500 123 138 1 9 312 5. 7 10 2.5N1 98 121 2 14 327 2.0

TABLE VIIContinued M echanzcal propertzes of Tl-Sn base alpha-beta alloys containing two beta stabllzzersCont1.nued

Tensile properties: Min. Bend p. s. i. 1,000 Percent Percent Radius Composition, Percent (Balance Elonga- Reduc- Titanium) tion in tion in VHN 0.2% Ultimate 1" Area Ofiset Strength L '1 Yield 10S11-4Mn-7.5Cr- 140 143 18 39 320 0 Sn-fiMn-4Fe. 146 152 8 359 3. 0 4. 3 10Sn-6Mn-10Mo 141 1 142 12 38 319 0.2 0. 8 132 142 13 32 370 1. 5 4. 0 143 147 9 385 1. 2 4. 6 147 149 8 25 340 2. 3 4. 8 147 153 8 26 350 1. 4 5. 4 137 144 10 33 361 0. 4/2. 3 4. 7 135 143 8 21 340 1. 5 4. 8 141 148 8 10 342 1. 9 4. 6 135 142 13 33 327 1. 0 2. 3/4. 7 133 146 2 6 346 B1 B1 149 157 9 19 387 1. 9 6. 1 139 149 10 12 351 1. 5 4. 8 96 113 16 44 299 1. 7 2. 5 104 116 14 313 1. 7 3. 5 127 138 13 31 333 1. 7 6. 6 122 137 12 29 333 4. 1 Br 122 132 3 2 5 331 3. O 5. 0 125 134 10 38 334 2. 5/4. 9 Br 117 122 8 24 297 2. 6 7. 0 104 105 3 1 4 317 2. 4 7. 0 133 138 3 8 360 1 6/3. 2 4. 9 117 124 15 36 330 2. 0 2. 0 136 138 15 39 319 0 0. 4 120 128 17 320 2. 0 2. 5 135 140 11 45 336 1. 5 3. 5 123 129 7 27 339 2. 5 4. 9 118 124 12 28 319 2. 0 2. 5 10Sn-2.50r5Ta. 126 134 11 30 317 2. 5 4. 9/6. 8 5Sn6.5Cr-7.5V.. 133 142 9 28 1. 2 10Sn2.5Cr-5V 116 129 12 28 319 0. 9 2. 6 10Sn2.5Cr2Nl 121 139 4 6 335 7. 0 Br.

148 156 16 38 387 1. 5 4. 7 140 153 11 23 0. 9 118 131 13 29 322 1. 5 6. 5 112 123 14 48 339 2. 7 2. 7 118 145 15 43 360 2. 7 5. 3 119 129 16 42 319 2. 6 5. 0 120 129 15 48 336 2. 6/5. 0 5. 0 137 140 10 33 319 2. 8 6. 2 108 124 10 30 325 5. 6 5. 2 124 142 14 36 363 2. 4 4. 7 116 123 11 27 342 5. 0 5. 0 116 123 17 51 327 2. 6 2. 6 120 130 10 39 312 2. 6 5. 2 118 129 13 37 329 2. 6 5. 1 113 119 11 v 34 274 2. 2 5. 1 114 125 10 24 330 2. 8 Br 130 140 v 13 41 348 1. 5 1. 5 10Sn5Cb2.5Cu 121 130 16 45 327 2 5/4. 9 4. 9 10811-5Ta 86 98 21 51 283 1. 7 1. 7 110 111 14 48 309 2. 8 2. 2 112 '120' 11 38 281 2. 3 5. 8 10Sn-5Ta2Ni 91 106 18 37 304 3. 4 5. 1 10Sn-5Ta20o 103 125 7 18 325 Br Bl 10Sn-5Ta-2.5Cu 94 105 16 32 317 2. 4 2. 8 108 118 10 39 289 1. 8 2. 1 107 112 7 40 258 0 1. 9 137 148 6 V 8 339 4. 8 B1 122 134 13 31 319 0. 8 4. 9/2. 4 114 124 6 21 1. 5 5. 6 93 16 35 2. 0 2. 5 110 130 12 20 5. 0 5. 0

97 118 12 27 4. 9 B1 107 124 13 27 4. 0 B1 105 14 30 2. 5 r 3.- 0 110 125 5 10 5. 0 5. 0 114 136 5 8 Br Br 96 106 18 43 2. 6 2. 6 122 131 13 a 24 i 3. 6 3. 6 135 136 7 42 0. 2 2. 6 138 141 9 35 4. 0 0 131 131 15 48 0 0 10Sn2Fe-5Mo50r. 135 135 16 47 0 0. 2 IOSn-ZMn-l.5Fe3.750r3.75Mo. 132 134 14 l 44 .0 0/5. 8 58n7.5Mn7.5Cr-0.20- 144 146 14 30 5. 2 5Sn8Mn4Gr-4M0. 121 138 19 52 0. 2 4Sn-5 Cr-5V-5M1L 131 137 14 36 1. 3 4Sn-3Cr-2.5Mo1.50u. 137 146 13 44 1. 0 4Sn-4Cr-2Fe2Cu 141 19 40 0. 7 4Sn1Mn2.50r1Fe-10u-2Mo-0.5V- 124 138 21 38 0. 9

1 The tensile strength was reached before the 0.2% ofiset yield strength.

2 Defective sample.

From the test results of Tables II to VII, inc., the following general conclusions may be drawn with respect to the eflect of single and multiple beta stabilizer additions to the titanium-tin base. The beta isomorphous elements V, Cb, Ta, Mo and Zr alone or in combinanation with each other, produce alloy having similar Mn which form systems containing sluggish eutectoid reactions, produce aloys which have high strengths, good ductility, fair thermal stability and are generally brittle as welded, except for low alloy contents of such additions. The elements with rapidly transforming eutectoids, Co,

Ni, Cu and W, produce alloys which have medium strengths, acceptable tensile ductility with borderline abend ductilities, poor. thermal stability, and with the exception of the Ti-10Sn5W alloy are intrinsically 18 A combinations of beta isomorphous elements with the ra'pideutectoid elements do'not result in improved ther- 1'7 brittle as welded, except for extremely low additions of true for combinations of. sluggish: eutectoid with rapid groups, multiple beta stabilizer alloys may be produced 5 eutectoid-elements. Over-all analysis of the test results which combine the good qualities-impanted -by the ele- The following Table VIII shows the effects on mechanical properties of additions of the alpha stabilizer aluminum tothe titanium-tin base, both with and without such elements. On the other hand, by judicious seled' tion and combination of the beta-promoters-from-one' of ma-l stability or weld ductility, and the sameis generally the groups above mentioned with those of the other 7 indicates that for maximum thermal stability and weld ments from the groups selected,-while tendingto-suppress ductility, the order of merit of the beta stabilizing eleand minimize their undesirable qualities. Thus, for exments is as follows: Cb, Mo, Ta, V, Cr, Mn, Fe, W, Cu, ample, the combination of beta isomorphous elements" Coand Ni. with the sluggish eutectoid elements results in alloys that 10 have improved thermal stability and weld ductility as' compared to those made with the sluggish eutectoid elements alone. 0n the other hand, thetest datarshows that Min; Bend 122135112322212224-9mem9mom Annealed Vickers Hardness Percent in Area Percent Elongation Reduction 8 7.1569909100911388 nmmm1m2211112121122111 additions of the interstitials, carbon, oxygenand nitrogen Ti-Sn base plus A1 alloys [Annealed condition] Tensile Properties: p. s. 1. 1,000

0.2 otr t Yield IODIDE TITANIUM BASE COMMERCIAL PURI'IY TITANIUM BASE Composition, Percent (Balance Titanium) 5 5 55 1122335T.011223355556655Zm1122335525611522222 f 1 555 5 10 5 11111111L222222222222ZZZ23333333am5555ZZmmmm Min. Bend '1 Percent Annealed Vlckers in Area Hardness 46924 79 221 3.1 373482 1 11 1 2958442 3 36 1 3177 306 17801 3631676 1 mwmaaammmmwmoemwamooaweemamememaeoeaanmmmnnmamaoaammawmwwnoa snwannanmw Percent Elongation Reduction Ultimate Strength TABLE VHI--Continued Tensile Properties p. s. LXLOOO 0.27 ofist Yield TiSn base plus A1 alloys-Continued COMMERCIAL PURITY TITANIUM BASE-Continued Composition, Percent (Balance Titanium) 1 Annealed 2 hours at 950 0.; other analyses annealed 2 hours at 850 0.

It will be observed from Table VIII that additions of additions of other elements to include alpha and beta aluminum to the titanium-tin base within the range of promoters, to form quaternary and higher component ing excellent tensile and other desirable propi. without Lerties as set forth in said application. Moreover, as applicants have The following Table IX shows the effect on mechanical properties 'of additions of the alpha stabilizer antirnon -to the titanium-tin base, with and without additions of 75 Qthe inters 'ti'als carbon, oxygen and nitrogen:

proportions set forth in the above Table B produce tensile 70 -a1loys hav strengths ranging upwards of 150,000 p. s.

undue embrittlernent.

shown in their copending application Serial No. 294,263

above mentioned, the titanium-tin-aluminum series described herein forms an excellent ternary base for further TABLE IX Ti--Sn base plus Sb alloys [Annealed condition] 1 Considerable weight loss occurred during melting.

TABLE XI Alloys of Ti-Sn base plus compound formers Si, Be, Ce, B, Te, etc.

[Annealed condition] Composition, Tensile Properties: percent (Balance p. s. i. 1,000

Titanium) Percent Percent Viekers Elongation Reduction Hard- Min.

in 1" in Area ness Bend T 0.2% Ultimate Sn Other Ofisei; Strength Yield IODIDE TITANIUM BASE 10 1GB 57 75 16 34 250 2. 1T8 61 78 17 48 232 2. 7 10 2.5Te 72 88 7 26 242 1. 1 1O 0.5B 54 72 21 38 236 1. 8 10 2.5'111 22 57 238 1. 9 10 181 97 16 38 305 1. 6 10 0.2138 70 12 22 273 1. 6

COMMERCIAL PURITY TITANIUM BASE 10 10o 1 80 94 17 39 285 2. 4 10 2.5Ce 75 92 15 33 276 3. 2 10 0.581 17 45 325 1. 5 10 181 97 109 17 35 330 5. 0 10 2S1 104 108 3 8 333 7. 0

' 1 Considerable weight loss occurred during melting.

The welding characteristics of the various types of alleys of the present invention, are described, and the weldable alloys thereof, covered by the above-mentioned co-pending joint application of the applicants .laffee and Ogden herein together with R. A. Happe, Serial No.

305,504, now abandoned. As therein shown, the all- ;alpha or substantially all-alpha titanium-tin base alloys '!of the present invention, containing up to about 16% tin, are weldable without serious impairment of ductilities,

: substantially throughout the entire range of analyses that such alloys are ductile in the cast or wrought condition.

The same is shown in said application to be generally true with respect to the beta or mixed alpha-beta titanium- 1 tin alloys obtained by additions of beta-promoters of the beta-isomorphous group, i. e., Mo, V, Cb, Ta and Zr,

tions of the sluggishly eutectoid beta promoters, Cr, Mn

and Fe, are generally productive of brittle welds when 1 present in substantial amounts, i. e., above about 23%, ialthough certain of the higher alloy analyses restricted -to.- Cr and/ or Mn additions are ductile as welded or can hav'e their ductilities restorcd by post welding heat treat- -ment as above mentioned, i. e., those containing up Ito about 78% M11 or up to about 18% Cr. The beta alloys formed by additions of Co, Ni, Cu and W having rapidly transforming eutectoids are intrinsically brittle :in the welded condition when these additions are present ;in excess of about 2 to 3%, i. e., their ductilities cannot be restored by post welding heat treatment. The compound forrners likewise impart intrinsic brittleness as welded to the titanium-tin base alloy when present in amounts exceeding about 2 to 3%.

Our investigations have established that the alloys in accordance with the invention containing about 10 to 15% tin are wholly contamination resistant at temperatures up to 1050 C. and probably higher regardless of the type of alloy, i. e., whether all-alpha, mixed alphabeta or all-beta. They have further established that there is a marked 'or critical reduction in contamination resistance commencing at about 5% tin as compared to that of the same alloy containing no tin. The tin addition produces free scaling alloys in most cases, but this tendency to free scaling appears to be reduced when large quantities 10f beta stabilizers are present.

The findings above stated are based on the test results set forth in the following Table XII, the data for which was obatined by arc melting IS-gram buttons of each of the compositions indicated in the table, including the tinfree alloy bases. The buttons were forged at 850 C. to about /s" square x 1%" long. Each forged billet was then descaled and sectioned into two samples. One sample was heated in air for four hours at 1050" C. and furnace cooled. The second sample received the same treatment in argon. These samples were furnace cooled to minimize any heat treatment effects that might have occurred with some of the alloys during cooling from the beta field. Weight-change data, scale appearance, thickness after wire brushing off the loose scale, and hardness penetration data were obtained for each specimen, with results as recorded in the table.

enemas 25 TABLE XII Oxidation test data for Ti--Sn base alloys containing Ta, W, Cb, V, Al, M0, Fe, Cr or Mn Since the binary Ti-455m alloy is free scaling, it is quite evident that the :aluminum present in the above-mentioned alloy is responsible for the adherent scale obtained. Also the Ti( -)Sn-,1OCr alloys had rather adherentscales t 5 with little loss in metalaby oxidation and no noticeable 00119115101 i g f gg ggf g' Air and contamination as measured by hardness. The Ti-lOCr I control alloy had a similar scale,but the underlying metal fi gfg flg g ggff MetaL Depth of Increase was highlycontaminated. Thus, when 10% chromium Weight Thickness omitamiT 'mV HN is present tin appears to .afiordthe.contamination resistggg 9%;? ggfigj 10 ance without the free scaling characteristics, thus in- Surface dicating utility of these alloys at elevated temperatures.

Our investigations have further shown that the ggg 2-? g 23 33 Ti--(5-15)Sn'-10Cr i iiljlj: I ii; i; .15 alloy, with and-without additions of up to 5% of one gin-5:31:31: $138 2% 5% 333 or more of imn, molybdenum n n n e 1OSn-5Ta 13.25 3% 30' 6 cellent elevated temperature hardnesses combined -with E- 52 1 -contamination-resistance attemperatures as-h1gh-as"800 5Sn-2.5W 23.80 36 40 6 to 900 F., and good hardness at temperatures up to 1100 lOSn-MW 323 i? Nil 30 to 1200 F. This is shown by the test results submitted ,:5Cb -V I '170 dnFEahle-XIII. r 35558; I 23 12 0 1 Nil ERefeI'ring ito'the. above data, a;comparison of the hard ush-sob. ra e? 26 TN11 1 .Nil3 0 mess-,valuesef the binary 'TiSn alloys with the binary g s- 1 $53 1.2; Ti..Cr alloys shows that it isthe chromium or betaaddi- 10Sn 5v 14%8 gs Nil gtionwhichqpromotesithe higher hardness at temperatures .;i fjjY 3 ii; i 2 200 up to 800 to 900 F. As further-shown by the=above ssnealue 7. 4 t .data, the combination of tinsand chromium provides an 12332323: E12 added hardening increment, due to the tin, which is main- 2 .5M0 t- 2.8 0 2 0-80 1280 tainedyatelevatedctemperatures. As further shown,-the ;-;Esl' 1:11;: 333 f8 3O substitutionof manganese, 'ironiandmolybdenum forpart 15Sne2:5M o. 2%.? :38 oflthe chromium, has .variedeffects. Iron additions re- I 21 i 50 sult m higherihardnesses, .whichtprevail. at temperatures-up N Nil 50 to, about 1200 F. Manganese. additions donot changethe l 28 .g .:hardness :of the Ti-iSn-PCn alloy, whilemolybdenum ad- 13 I 0 F38 ditions produce somedecreasein hardness which prevails 5 1 NH g at all temperatures referred to. On the basis of hardness 3 2 .alonegtheTi5Sn10Cr5Fe alloyis best. However,

812 H 2 Nil 50 -onthebasis ofstrong and ductile room temperatureprop- 6 -3 28 c ties as well. as elevated temperature contamination re- 0 1 0 8D 140 40 sistance and hardness,:the TiSn.-1Cr(Mo, Mn) alloys 3 3 $2 are of best all-aroundiutility.

3: 8% N l N .1 Therg orgl 'tgrligerature properties of these alloys are i i Y given in a e a j i y 2 I The'alloys ofthe invention'may be made by melt castg egg in all coldamold,-imployiing aln electthric ,arc in an ilnerfi 1 Nil 1 a osp ere, or may e pro uce 1111 0 er ways in w ic 1%;? 23 ,Nil $711 -thewhaldoyishrencllered moltenbeforecasting.

6:6 9 ..40; i ere t ea loys are to be used in the formof sheets, i the minimum bend ductilities may range as high as 20T, i '50 and where they are toubeused in massive form, as in A abovew stated, the majority of the vspecimensWqere .found to be iree scaling, but thisayas notqsoizof the Ti--5 Snw2Al; alloy. This zalloy =hady-a very adherent scale which could not be removed -by 'wire brushing.

forgings, 'the percent tensile elongationmay range as low as .1 .or.2%. Minimum bend ductility T is defined as theminimum radius to 'whichiia :specimen can be bent through anangle of" without fracture, expressed as-a 55 multiple of thespecimen thickness.

TABLE XIII Hot hardness values of Ti-- Sn-base alloys for 'Composition percent F. 250 F. ,500 F. 750 F. 1,000 F. 1,250 F. 1,500 F 80F.

;(B alance Titanium) 219 195 141 116 72 33 233 240 221 163 133 107 60 :23 ,287 270 235 189 152 132 71 27 292 306 276 223 123 32 18 476 297 235 269 247 51 i 27 357 355 294 261 235 144 42 24 359 326 313 275 254 55 26 339 360 327 279 265 179 58 32 377 389 353 322 315 244 92 37 409 315 290 246 240 75 t 33 346 5Sn-100r-5Mn 324 814 286 271 186 68 31 376 M11 377 340 i 269 235 106 46 1 Hardness at room temperature after being heated to 1500:F. Annealed 2 hours 210850? 0.

prior to testing; other analyses annealed at 7009 O.

TABLE xrv Mechanical properties of Ti-SnCr-base alloys for elevated temperature service at 1,300 F air cooled to room temperature] i; These alloys were 980 0. forged, hot rolled at 1,400 F. to 0.080 inch, descaled, hot rolled to 0.040 inch, held 15 minutes at 1,300 F., furnace cooled to 1,100 F., and

It will be observed from the data in the tables above set forth that the alloys of the invention have ultimate tensile strengths at least 10% in excess of the unalloyed titanium base metal, and in the vast majority of instances, ultimate strengths at least 30 to 50% in excess of the unalloyed titanium base metal.

In the appended claims, by the expression beta promoters is meant'elements of the group molybdenum, vanadium, columbium, tantalum, zirconium, manganese, chromium, iron, tungsten, nickel, cobalt and copper; by the expression alpha promoters is meant elements of the group antimony, silver, cadmium, zinc, thallium, bismuth and lead; by the expression compound formers is meant elements of the group cerium, boron, arsenic, sulfur, tellurium, silicon and beryllium.

What is claimed is:

l. A titanium base alloy consisting essentially of about: 0.5-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, and 0.5-49% of at least one beta promoter, said alloy having a tensile elongation of at least 2% and a tensile strength at least 10% in excess of that of the corresponding titanium-tin binary alloy.

2. A titanium base alloy consisting essentially of about: 05-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, 05-20% of at least one alpha promoter and 05-49% of at least one beta promoter, said alloy having a tensile elongation of at least 2% and a tensile strength at least in excess of that of the corresponding titanium-tin binary alloy.

3. A titanium base alloy consisting essentially of about: 05-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, and 0.1-3% of at least one compound former selected from the group consisting of cerium, boron, arsenic, sulfur, tellurium, silicon and beryllium,

said alloy having a tensile elongation of at least 2% and a tensile strength at least 10% in excess of that of the corresponding titanium-tin binary alloy.

4. A titanium base alloy consisting essentially of about: 0.5-23% tin, up to 1% carbon, up to 0.5 oxygen, up

to 0.4% nitrogen, 05-20% of at least one alpha promoter, 0.5-49% of at least one beta promoter and 0.1- 3% of at least one compound former selected from the group consisting of cerium, boron, arsenic, sulfur, tellu- 05-49% of beta promoters, 0.5-20% of alpha promoters and 0.1-3% of compound formers selected from the group consisting of cerium, boron, arsenic, sulfur, tellurium, silicon and beryllium, balance titanium.

6. An alloy consisting of about: 0.5-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, and 0.5-49% of at least one beta promoter, balance titanium.

7. An alloy consisting of about: 0.5-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, and 0.5-20% of at least one alpha promoter, and 0.5- 49% of at least one beta promoter, balance titanium.

8. An alloy consisting of about: 05-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, and 0.1-3% of at least one compound former selected from the group consisting of cerium, boron, arsenic, sulfur, tellurium, silicon and beryllium, balance titanium.

9. A titanium base alloy consisting essentially of about: 0.5-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, and 0.5-49% of at least one beta isomorphous promoter selected from the group consisting of molybdenum, vanadium, columbium, tantalum and zirconium, said alloy having a tensile elongation of at least 2% and a tensile strength at least 10% in excess of that of the corresponding titanium-tin binary alloy.

10. A titanium base alloy consisting essentially of about: 05-23% tin, up to 1% carbon, up to 0.5 oxygen, up to 0.4% nitrogen and 0.5-5% of at least one rapidly eutectoid beta promoter selected from the group consisting of cobalt, nickel and copper, said alloy having a tensile elongation of at least 2% and a tensile strength at least 10% in excess of that of the corresponding titanium-tin binary alloy.

11. A titanium base alloy consisting essentially of about: 5-15% tin, 10% chromium and up to 5% of metal of the group iron, molybdenum and manganese, characterized in being highly resistant to atmospheric contamination at temperatures up to about 2000 F. and in undergoing no substantial reduction in hardness at temperatures up to about 800 F.

12. A titanium base alloy consisting essentially of about: 05-23% tin, up to 1% carbon, up to 0.5% oxygen, up to 0.4% nitrogen, 05-20% of at least one sluggishly eutectoid beta-promoter selected from the group consisting of chromium, tungsten, manganese and iron, but not to exceed 10% manganese and 7% iron, said alloy having a tensile elongation of at least 2%, and a tensile strength at least 10% in excess of that of the corresponding binary alloy.

References Cited in the file of this patent UNITED STATES PATENTS 2,596,489 Iatfee et al May 13, 1952 2,614,041 Finlay et al Oct. 14, 1952 2,622,023 Frazier Dec. 16, 1952 2,661,286 Swazy Dec. 1, 1953 2,668,109 Croft Feb. 2, 1954 2,669,513 Jaftee Feb. 16, 1954 2,669,514 Finlay Feb. 16, 1954 2,700,607 Mcthc Ian. 25, 1955 

4. A TITANIUM BASE ALLOY CONSISTING ESSENTIALLY OF ABOUT: 0.5-23% TIN, UP TO 1% CARBON, UP TO 0.5% OXYGEN, UP TO 0.4% NITROGEN, 0.5-20% OF AT LEAST ONE ALPHA PROMOTER, 0.5-49% OF AT LEAST ONE BETA PROMOTER AND 0.13% OF AT LEAST ONE COMPOUND FORMER SELECTED FROM THE GROUP CONSISTING OF CERIUM, BORON, ARSENIC,-SULFUR, TELLURIUM, SILICON AND BERYLLIUM, SAID ALLOY HAVING A TENSILE ELONGATION OF AT LEAST 2% AND A TENSILE STRENGTH AT LEAST 10% IN EXCESS OF THAT OF THE CORRESPONDING TITANIUM-TIN BINARY ALLOY. 